The invention relates to a driven device for keyway broaching, comprising a broaching carriage that is guided by one or several linear guides in a housing. The broaching carriage is driven by a gear assembly that converts a rotational movement of the drive shaft into a linear movement.
Devices for keyway broaching are disclosed, for example, in EP 2 402 099 A1 and in RU 606 690.
Keyway broaching is a method for producing keyways with a geometrically determined cutter. The chip removal is realized during the working stroke by the cutter of a broaching tool. The subsequent return stroke returns the broaching tool into its initial or starting position. In order to prevent that the cutter during the return stroke scrapes across the base of the keyway and thereby becomes blunt or even breaks off, the broaching tool during the return stroke must be somewhat lifted or tilted.
Simultaneous with the working and return stroke the feed (forward or advancing movement) is carried out until the desired keyway depth is reached. After having reached the keyway depth, several additional strokes are carried out without forward movement in order to reach a keyway parallel to the working stroke.
Because the cutting forces during broaching are relatively high, a stiff and robust clamping action and guiding action of the broaching tool are required. On the other hand, the same broaching tool, as mentioned above, must be lifted somewhat for the return stroke.
Since devices for keyway broaching are used in machine tools, it is advantageous when the lifting action of the tool during the return stroke can be carried out as needed in the direction of the positive X axis or in the direction of the negative X axis (see double arrow 38 in the Figures). It is then possible to machine workpieces with very large inner diameters as well as with very large outer diameters with the same device for keyway broaching in a machine tool, in this case a lathe.
The invention has the object to provide a robust, compact, and high-performance device for keyway broaching that enables a process-reliable manufacture of keyways in highest quality with minimal cycle times.